From the aerial point of view, there is a special point, directly above a person or object, where the compression of space reaches a maximum: the perpendicular. Imagine standing on the street, looking straight ahead, and falling forward while rising, through a 90-degree rotation. The scene gradually changes; the horizon starts at eye-level, but as one falls forward, it soon disappears as a reference point. Perspective disappears with the horizon, and the compressive distortion of foreshortening increases. As the obliquity of the angle of view increases, you reach the ‘bird’s eye’ elevation; then, closer and closer to the perpendicular, until it arrives with a shock; abstraction becomes real; the illusion of space disappears, replaced by an unfamiliar reality. As if a theorem of calculus had become a tangible physical reality, this simple rotation through 90 degrees reaches a mysterious zero-point. It is a real point, and yet one filled with infinities. It is the defining end point on a continuum of illusion: reality.